| Fetal distress refers to the combination of symptoms that endanger the health and life of the fetus in utero due to acute or chronic hypoxia,with an incidence of 2.7%to38.5%.Acute fetal distress usually occurs during delivery.Chronic fetal distress usually occurs in the third trimester of pregnancy,but it is often manifested as acute fetal distress after delivery[1].Among the high risk factors affecting fetal safety,fetal distress in utero is a relatively common one,if not found in time or handled improperly,may lead to fetal asphyxia.In addition to the adverse pregnancy outcome,fetal distress may also affect the growth and development of perinatal infants.At the same time,it can be seen from a large number of literature reports that fetal distress in utero will also threaten maternal safety,adverse pregnancy outcome will increase the physical and mental burden of pregnant women,so early diagnosis and treatment is needed.With the continuous development of fetal distress research,more and more scholars have proposed that early and effective screening,detection of intrauterine distress and targeted treatment can reduce adverse pregnancy outcomes.There are many ways to screen fetal distress in utero.Fetal heart monitoring is commonly used in the past,which has little impact on pregnant women and fetuses,but the specificity and sensitivity are affected by multiple factors and not high.With the more and more extensive application of ultrasonic diagnosis in clinic,ultrasound has been proved to be of good value in pregnancy examination,especially the wide application of color ultrasound,which is recognized for its non-invasive and repeatable operation.To detect the blood flow indexes of umbilical artery and middle cerebral artery by color Doppler ultrasound,so as to understand the development of the fetus,is the focus of ultrasound research in obstetrics.Objective:By establishing the model of pregnant mice with chronic hypoxia,the relationship between hypoxia and cerebral microvascular density of fetal mice was obtained,and the possible causes of the changes in the mechanical indexes of cerebral arterial blood flow caused by fetal distress were found.To explore the value of color Doppler ultrasound detection of fetal umbilical artery S/D value,umbilical cord blood flow RI,umbilical cord blood flow PI,middle cerebral artery RI,middle cerebral artery PI,brain placenta rate,middle cerebral artery PSV（Mom）combined with fetal heart monitoring,age and gestational age in evaluating fetal distress,and to provide a new method for clinical prediction of fetal distress.In order to provide a more reliable basis for predicting intrauterine distress when there is difference between ultrasonic detection value and fetal heart monitoring.Methods:1.In this case-control study,66 patients diagnosed with intrauterine distress admitted to the Department of Obstetrics and Gynecology of Jinan Maternal and Child Health Hospital from January 2019 to October 2022 were selected as the study group,and 107healthy women admitted to the hospital during the same period were selected as the control group.A total of 101 pregnant women who underwent fetal hemodynamic index examination and fetal heart monitoring examination in Jinan Maternal and Child Health Hospital from November 2022 to December 2022 were selected for cross-sectional study.According to the model obtained from the case-control study,the results were calculated and divided into the predicted positive group and the predicted negative group.Two groups of subjects were included in the case-control and cross-sectional studies Color Doppler ultrasound was used to detect fetal umbilical artery S/D value and converted value,umbilical cord blood flow RI value and converted value,umbilical cord blood PI value and converted value,middle cerebral artery RI value,middle cerebral artery PI value and converted value,cerebral placenta rate and converted value,middle cerebral artery PSV（Mom）combined with fetal heart monitoring,age and gestational age.The two sets of values were compared and analyzed.2.SPSS25.0 software was used for analysis and processing.Count data of pregnant women were compared by the number of cases,Chi-square test was used for comparison between groups,measurement data were described by（±s）,and LSD-t was used for comparison between groups.Clinical diagnosis was used as the gold standard to analyze the sensitivity and specificity of related indicators to predict fetal distress.P<0.05indicated statistical difference.The predictive model of fetal distress was obtained by binary Logistic regression.In addition,the sensitivity,specificity and area under ROC curve of the combined model to predict fetal distress were obtained through the numerical values of cross-sectional studies of each index of the model,so as to verify the clinical effectiveness and repeatability of the combined model.3.5 pregnant mice were randomly assigned according to the experimental group,3pregnant mice and 2 pregnant mice in the control group.On the 15th day of pregnancy,pregnant mice in the experimental group were placed in the hypoxia simulation chamber until delivery,while the control group had normal oxygen concentration until delivery.The expression of hypoxic-induced-factor-1αprotein in the brain tissue of the two groups was detected respectively,and the number of CD34+cells in the brain tissue of the two groups were detected respectively under high magnification microscope.Results:1.There was no significant difference in age and underlying diseases between the study group and the control group in the case-control study and cross-sectional study（P>0.05）.2.Compared the conversion values of umbilical artery S/D,umbilical artery RI,umbilical artery PI,middle cerebral artery RI,middle cerebral artery PI,fetal heart monitoring grading,fetal ultrasound biophysical score and brain placenta rate of the study group and the control group in the case control study,the results showed that,The umbilical artery S/D conversion value and fetal heart monitoring grading value of the research group were significantly higher than those of the control group,while the middle cerebral artery PI conversion value and fetal ultrasonic biophysical score of the research group were significantly lower than those of the control group,with statistical significance（P<0.05）.3.The model formula for diagnosing fetal distress in utero was 10.565-0.376*（gestational age）+6.796（umbilical artery S/D conversion value）-5.952*（middle cerebral artery RI value）-2.779*（middle cerebral artery PI conversion value）+4.315*（fetal heart monitoring grading value）-0.512*（fetal ultrasound biphysical score）In the case control study,the sensitivity was 81.8%,the specificity was 87.9%,and the area under ROC curve was 0.92.The sensitivity of the model was 92.6%,the specificity was 86.5%and the area under ROC curve was 0.93.Compared with the combined prediction model,there were differences in specificity and sensitivity between the single detection value and the combined prediction model.The area under the ROC curve showed that the combined prediction model was more valuable.4.All 11 cases of end-diastolic blood flow disappearance of umbilical artery were in fetal distress.Because S/D value,RI value and PI value of umbilical blood flow could not be obtained,they were not included in the statistics.5.Compared with the control group,the expression of hypoxia-induced-factor-1αprotein in the brain tissue of the experimental group was higher,and the density of CD34+cells in the brain tissue of the experimental group was higher under the same high magnification field of vision（P<0.05）.Conclusion:Through the successful construction of a model of pregnant mice with chronic hypoxia,it is concluded that chronic hypoxia can cause cerebral vascular remodeling in fetal mice,resulting in increased microvascular density,which can further explain the changes in the mechanical indexes of blood flow in the cerebral arteries caused by fetal distress.The sensitivity,specificity and area under ROC curve when color Doppler ultrasound was used to detect fetal umbilical artery S/D conversion value,middle cerebral artery PI conversion value,middle cerebral artery RI value,fetal ultrasound biphysical score combined with gestational age and fetal heart monitoring grading value in the diagnosis of fetal distress were compared with that of single detection of umbilical artery S/D conversion value,middle cerebral artery PI conversion value and fetal heart monitoring grading value High;In this study,a prediction model of intrauterine distress based on ultrasonic detection of hemodynamic indicators combined with fetal heart monitoring was obtained by using binary logistic regression method,and the model was verified through cross-sectional study,which increased the effectiveness and repeatability of the model,which has important practical significance for improving maternal and infant health,and can be popularized and applied in clinical diagnosis. |
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